And I'm Steve Inskeep. Good morning. A trial begins today in a case that once again puts a spotlight on Florida's Stand Your Ground self-defense law. That's the law that allows people to use deadly force to defend themselves without first trying to retreat. The law came to national attention a couple of years ago when a Neighborhood Watch volunteer George Zimmerman fatally shot an unarmed teenager Trayvon Martin.

Zimmerman was eventually acquitted of all charges in that case. Now a new case of 47 year old Michael Dunn who is charged with first degree murder in the shooting of 17 year old Jordan Davis has revived attention on the law. Dunn - who is white - says he was in fear for his life when he shot Davis, who was an unarmed black teenager. NPR's Greg Allen reports it all began in a dispute over loud music.

GREG ALLEN, BYLINE: It was in November of 2012 - the day after Thanksgiving. Michael Dunn pulled into the parking lot of a convenience store in Jacksonville, Florida with his girlfriend after attending his son's wedding. While his girlfriend went inside to buy a bottle of wine, Dunn got into an altercation with the occupants of an SUV parked alongside. He asked them to turn their music down and at first they did. But then, Dunn said later in a videotaped interview with detectives, they turned the radio back up.

(SOUNDBITE OF TAPED INTERVIEW)

MICHAEL DUNN: And I don't know if they're singing or what, but it's like they're saying kill him. So I put my window down again and I say, excuse me, are you talking about me?

ALLEN: The person in the right backseat - who turned out to be 17 year old Jordan Davis - Dunn said was really agitated.

(SOUNDBITE OF TAPED INTERVIEW)

DUNN: You know, I'm still not reacting but then, this guy, like, goes down on the ground and comes up with something. I thought it was a shotgun. And he goes you're dead, bitch and he opens his door.

ALLEN: That's when Dunn reached into his car's glove compartment, took out a nine millimeter pistol, and fired four shots into the SUV.

(SOUNDBITE OF SURVEILLANCE TAPE)

UNIDENTIFIED WOMAN: Oh, somebody's shooting. Somebody's shooting out of their car, I swear to God.

ALLEN: That's audio from a surveillance camera inside the convenience store. The SUV with Davis and three other young African-American men then pulled out of the parking lot. Dunn says as they pulled away, he fired four more shots into the SUV. Davis was pronounced dead at a local hospital. By the time police arrived on the scene, Dunn and his girlfriend had left.

Police got his license number from a witness and arrested him the following day at his home, more than 150 miles away. In the interview after his arrest, detectives told Dunn there was no evidence Davis or anyone else in the car had a gun.

(SOUNDBITE OF TAPED INTERVIEW)

DUNN: When you say he didn't have a weapon. He's on the ground, and you put something up on the thing and then gets out, I thought it was a shotgun. Or a stick, or, you know, some kind of weapon, but...

ALLEN: From the time of Jordan Davis's shooting, the case has drawn national attention. And it's compared to another high-profile trial - Neighborhood Watch volunteer George Zimmerman's shooting of Trayvon Martin. Because of his self-defense claim, Zimmerman wasn't charged for weeks and was released on bail.

In this case, Michael Dunn was arrested and charged as soon as police could find him. He's been denied bail. As in the Zimmerman case, the state attorney is Angela Corey. At his arraignment, she explained why he was charged with murder.

ANGELA COREY: We look at all the facts and circumstances in any gun case. We consider how the gun was obtained, number of shots, number of victims, circumstances surrounding the killing.

ALLEN: Florida's self-defense law - sometimes called Stand Your Ground - will play a key role. Dunn's lawyer, Cory Strolla, says his client will argue that when he shot and killed Davis, he was acting in self-defense.

CORY STROLLA: The evidence will show and we believe we're going to show that these gentlemen in the car not only gave verbal threats of death but were attempting to get out of the car to attack Mr. Dunn. And that's when he fired the shots.

ALLEN: In their interview with Dunn, detectives said none of the witnesses at the convenience store saw Davis or anyone else get out of the SUV. Jordan Davis's parents have already settled a wrongful death lawsuit filed against Dunn. Davis's mother, Lucia McBath, now is an anti-gun violence activist who has campaigned to repeal Florida's Stand Your Ground law. She doesn't believe the law applies in this case.

LUCIA MCBATH: I mean, there again, how are you going to claim Stand Your Ground against unarmed individuals? How can they pose a threat to you? No drugs, no alcohol, no guns, nothing.

ALLEN: That will be a question for the jury. Jury selection begins today in Jacksonville. Greg Allen, NPR News, Miami. Transcript provided by NPR, Copyright NPR.